Trees, grasses and wildflowers are endless as the small, one-person trail cuts through the Wisconsin landscape. The trail is a way to remember the once-great glaciers that shaped the landscape of the state, and a place to view the spectacular rock formations they left behind when they melted.

But even though the history of the glaciated trail is older than Marathon County itself, it's seen a lot of change in the last few years. Volunteers have been hard at work, moving heavy stones and creating new paths. Their vision: to create a trail that will keep hikers coming back for years to come. In central Wisconsin, new work on a parallel trail for mountain bikers also aims to make the most of the region's recreational potential.

"Locally, it's a really cool way to get out there and enjoy nature," said Gail Piotrowski, a volunteer for the Ice Age Trail Alliance. "I've learned a ton about birds, wildflowers, rocks and geology."

The Ice Age Trail spans more than 1,000 miles through the state, winding its way from Sturgeon Bay, down and around Madison, up through Marathon County near Wausau and ending at the Minnesota/Wisconsin border. The trail takes its odd shape because it follows the lines of where the glaciers stopped. The trail, which was formally created in 1970, highlights the landscape features that were left behind when the glaciers melted after the ice age. The trail is also one of 11 National Scenic Trails, a group that includes the popular Appalachian Trail on the East coast.

"This trail brings people from all across the country," Piotrowski said. "Sections have been featured in backpacking magazines."

Hiking is just one of the many options for recreation in Wausau.

The city also has a world-class whitewater kayaking course, miles and miles of mountain biking trails and skiing, just to name a few.

There isn't data about how many people hike throughout Marathon County, but a study done in 2012 found that 1.25 million users passed over the trail a year, either hiking in sections or the entire trail. And those users spent money locally that year, contributing an estimated $113 million.

The Ice Age Trail has been formally marked since the '70s, it's still in need of routine updates. And that's where the Ice Age Trail Alliance comes in.

In Marathon County, the nearly 44 miles of trail have undergone major updates, most notably, the addition of two board walks along the Plover River segment, that allow hikers to move through a cedar swamp without muddying their shoes.

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Hikers walk along the board walk on the Plover River segment of the Ice Age Trail.(Photo: Laura Schulte/USA TODAY NETWORK-Wisconsin)

There have also been updates to some of the paths that used to go along old mining roads or logging paths, Piotrowski said. Moving those paths has been labor intensive, but it's also allowed opportunities for other types of recreation to move into the area, like mountain biking.

Mountain biking isn't allowed on the Ice Age Trail, because bikes tend to compact trails and make the terrain more difficult for walkers, Piotrowski said. The section of the trail that once wound its way along the west side of the landfill near Ringle was moved to the east side, making a space for the Central Wisconsin Off-road Cycling Coalition to place a new trail.

"We've been working for three years to bring more recreation to the area," said Matt Block, the vice president of CWOCC. "And because of the easements, we couldn't bike on the Ice Age Trail. We couldn't even cross it."

Because the trail was so close to the Mountain Bay Trail, it was hard for mountain bikers to avoid that part of the Ice Age. But now, construction has started on a new biking course, one that will be more friendly for beginners than almost any other trail in the area.

"Because it will be machine-built, it will be smoother," Block said. "And there's an interesting elevation change out in Ringle— like a little roller coaster on a bike."

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Wild flowers are among some of the sights to be seen along the Ice Age Trail.(Photo: Laura Schulte/USA TODAY NETWORK-Wisconsin)

CWOCC intends to add nearly 10 miles of new trail in the place of the old Ice Age Trail. And on the other side of the landfill, the trail will continue on, thanks to the hard work of volunteers. Piotrowski expects part of the new segment to open in August.